Flight time is an useful application to calculate the elapsed time between two hours as Flight Time, Duty Time, Flight Plan calculations, Flight Log and more.
You can use it for cumulative time or any other time calculation.
Full version includes the resting time calculation during long flights using 3 or 4 Pilots where you can choose from 2 to 5 resting lapses. Even is possible not to include some time for the resting calculation as time after takeoff or before landing.
Flight Time was specially designed for Flight Crews.